Automobile seat with a backrest frame

ABSTRACT

An automobile seat includes seat frame and backrest frame portions, each of which includes a pair of opposite side braces of generally U-shaped configuration which face away from the seating surfaces of their respective side frame and back rest frame portions. The side braces of the side frame and back frame portions define open channel-like areas for accommodating adjusting units of the seat.

BACKGROUND AND SUMMARY OF THE INVENTION

This invention relates to an automobile seat with a backrest frameand/or a seat frame, each of which has open side braces placed laterallyand essentially U-shaped in cross section.

Frame constructions with side brace hollow profiles open on one side areknown. They are used primarily with small thicknesses to reduce weight.Of course, special measures are necessary to make such side brace hollowprofiles rugged and torsionally rigid. This applies particularly to theside braces of backrest frames, to the top of which a safety belt mayalso be fastened.

As measures for achieving the desired load capacity and torsionalrigidity of the side braces, it is known how to give side braces,generally made of rod material, a special cross sectional profile, whichcan be symmetrically C-shaped, U-shaped, or Z-shaped for example. It isalso known how to arrange the side braces of backrest frames so that theaxis of the largest moment of resistance points approximately in thedirection of action of the safety belt, i.e., diagonally to the longdirection of the seat (cf. DE-OS 36 24 295). However, this then resultsin a larger structural volume for the backrest which is inherentlydesired to be particularly flat, and a smaller moment of resistance inthe direction of the forces acting approximately perpendicular to thebackrest that are especially large in the area of linkage of thebackrest frame to the seat bottom and/or to the seat frame.

It is the purpose of this invention to propose a design for the sidebraces of the backrest frame and/or of the seat frame that can absorbhigh forces from all important directions of application, and at thesame time is torsionally rigid and nevertheless does not require alarger structural volume for the seat, and particularly not for thebackrest desired to be of flat design.

This problem is solved pursuant to the invention by the fact that theopen side of the side braces extends away from the top of the seat usedby the passenger and that the back of the side braces facing thepassenger has such a large width, at least in some areas, thatstructural adjusting units for the seat can be placed in the cavityenclosed by the side braces, i.e., in the inner profile space of theside braces. It is desirable to provide that the adjusting units locatedin the profile space are fastened to both side walls of the side brace.

Particularly beneficial side braces pursuant to the invention also havea diagonal surface that is placed at the center of the seat, and a sidebrace back width that changes relative to the backrest frame, whichdecreases essentially conforming to the outer contour of the backreststarting from the bottom of the side braces toward the head of thebackrest frame.

With regard to the backrest frame, it is beneficial also to modify thestructural depth of the side braces, specifically increasing toward thebottom of the side braces. At this bottom end of the side braces, i.e.,at their base, the pivot axis is then shifted forward toward thepassenger for the tilt adjustment of the backrest, i.e., it is locatednext to the back of the side braces. On the other hand, the linkagepoints of the tilt adjusting mechanism are then to be positioned on theside braces toward the rear, i.e., away from the passenger next to theopen side of the side braces. This results in a particularly effectivelinkage of the side braces of the backrest frame to the seat bottom orthe seat frame that can handle all forces properly.

As a result, the construction pursuant to the invention provides thatthe side braces have a wide back profile with a wide inner profile spaceto hold adjusting units for the seat, and at the same time because ofthe diagonal surfaces designed in them and because of a certain outercontour shape, and also because of the mentioned structural depthmodification toward the deep and wide base of the side braces, theyconstitute a polyhedral object that can absorb large forces from allimportant directions of application with torsional rigidity.

The placement of the adjusting units for the seat in the inner profilespaces makes it possible for the structural volume of the seat to remainsmall in the desired manner. This applies particularly to the desiredflat design of the backrest, which undergoes no enlargement of thebackrest thickness in the particularly critical central area of thebackrest because of the integrated placement of the backrest adjustingunits in the cavity of the side braces on the outside and at the side.

An additional extreme reinforcement of the side brace hollow profile isachieved at the same time by the integrated placement of the adjustingunits for the seat, for example a latching unit, an adjusting motor, orthe like, in the inner profile space of the side braces, and thesimultaneous fastening of the adjusting units to both side walls of theside brace.

Nevertheless, the large back widths of the side braces necessary for theutilization of the inner profile space do not interfere with seatcomfort, since the backs of the side braces have a diagonal surfacelocated at the center of the seat that brackets the backrest and/or theseat surface for the body of the passenger and at the same time supportsthe body of the passenger on the side.

The "polyhedral object" described above as a side brace for automobileseats is a new design principle that intentionally avoids the use ofextruded, canted, or rolled bar profiles for the side braces of backrestframes and/or seat frames. Nevertheless, the polyhedral object can bemanufactured economically from sheet metal by means of a form tool, forwhich the light construction can be taken into account by appropriateoptimization of the sheet thicknesses.

With regard to the side braces of a seat frame, a desirable refinementof the invention provides that a second brace (called the bottom bracebelow) is arranged beneath each of the side braces of the seat framewith U-shaped cross section open at the top, and that the side bracesare adjustable relative to their bottom braces by adjusting units thatare located in the cavity enclosed by the side braces.

It is particularly desirable for the side braces to overlap the bottombraces with each outer side wall. The bottom profile can be almostcompletely covered over by this, and the side wall of the side bracedrawn downward can advantageously be used for the attachment of handlesor other manual operating devices, without the risk that the hand of thepassenger will get between the side brace and the bottom brace.

DESCRIPTION OF THE DRAWINGS

An example of embodiment of the invention will described in detail belowwith reference to the drawings. The drawings show:

FIG. 1 illustration in perspective diagonally from the front of anautomobile seat pursuant to the invention;

FIG. 2 the seat of FIG. 1 diagonally from the back.

DESCRIPTION OF THE INVENTION

The automobile seat illustrated shows the metal construction withoutcushion parts or cover. It consists essentially a backrest frame 3 withadjustable head part 4 and a seat frame 5.

The backrest frame 3 has two side braces 6 and 7, each of which has awide, front wall or closed back 8 and 9 with a diagonal surface 10 and11 positioned sloping toward the center of the seat.

This produces an inner profile space 12 and 13 accessible from the rearthat can be utilized for the integrated placement of structuraladjusting units for the seat in the profile space.

In the example of embodiment illustrated, there are adjusting units inthe form of rod and clamp devices 14, 15 or 16, 17 or 18, 19 in theinner profile space. It can be seen that each of the clamping devices isfastened at both ends, i.e., to both side walls 20, 21 or 22, 23 of theside braces and thus provide additional reinforcement for the sidebraces 6 and 7.

The outer side walls 20 and 23 of the side braces 6 and 7 are providedwith shoulder surfaces 24 and 25 corresponding to the outer contour ofthe backrest, and as best seen in the outer lateral surfaces 20 and 23,the structural depth of the side braces 6 and 7 measured between theback and the open side increases toward the bottom of the side braces.

As a result, the illustrated side braces 6 and 7 are thus a "polyhedralbody", each of whose individual surfaces (specifically the back surface8, 9, the diagonal surfaces 10, 11, the side walls 20, 21 or 22, 23, andthe shoulder surfaces 24, 25) has its own arrangement in space thatdiffers from the others, so that side braces are formed with extremelyhigh torsional rigidity that can absorb large forces from all importantdirections of application. The pivot axes 26 and 27 for the tiltadjustment of the backrest are located at the bottom of the side braces6 and 7 next to the particular back surfaces 8 and 9 of the side braces.These pivot axes are intentionally displaced forward toward thepassenger and act together with the pivot axes 28 and 29 displacedtoward the back, which serve for the linkage or fastening of the rod andclamp devices 14 and 16 to the side braces. Thus, the axes 26, 27 and28, 29 at the bottom base of the side braces are relatively far apartand the forces can be particularly well transmitted through the sidebraces 6 and 7 to the seat bottom, or as in the case illustrated, to theseat frame.

The seat frame also has side braces 30 and 31 that have a wide backsurface 32 and 33 so that structural adjusting units for the seat can beplaced in the cavity enclosed by the side braces, i.e., in their innerprofile space.

In the example of embodiment illustrated, a bottom brace 34 and 35 isplaced below each of the side braces 30 and 31 of the seat frame, whichenclose a cavity with the side braces in which is located the rod andclamp unit 36, 37. This rod and clamp unit is used to spread apart inthe vertical direction the front ends of the side braces 30, 31 from thebottom braces 34, 35 by means of the connecting rods 38, 39 to makepossible a simple tilt adjustment of the seat frame 5 relative to thebottom braces.

The side braces of both the backrest frame and the seat frame areconnected to one another in the usual way by cross-struts 40-45. Othertransverse connectors can also be used instead of such cross-struts, forexample in the form of cross-plates.

A head part 4 that can pivot around the axes 46 and 47 is fastened tothe top of the backrest frame 3, which is adjustable in its sloperelative to the backrest frame 3 by means of the rod and clamp unit 18,19. This rod and clamp unit is placed inside the inner profile space ofthe side brace of the backrest frame, so that it requires no additionalinstallation volume and is kept away from all cushioning materials ofthe seat (not shown) for its functionability.

The basic operating structure of all of the rod and clamp unitsmentioned above is known from DE-OS 34 20 103, and is operated by meansof Bowden cables whose actuating devices (not shown) are fastened to oneof the outer side walls 48 or 49 of the side braces 30, 31 of the seatframe 5, which essentially completely overlap the bottom braces 34, 35from the outside, so that no risk of injury exists in manipulating theoperating mechanisms of the Bowden cables.

We claim:
 1. In an automobile seat of a type including a backrest frameincluding a pair of opposite side braces, each of said side braces beingof elongated, open, generally U-shaped channel-like configuration andincluding a front wall having a length and a width, and spaced inner andouter side walls, each of said side braces defining an open interiorcavity, an improvement comprising the side braces of said backrest framebeing positioned such that the front walls thereof face forwardly andsuch that the interior cavities thereof open rearwardly, and seatadjusting means in said open interior cavities, the widths of said frontwalls being sufficient to accommodate said seat adjusting means in theopen interior cavities in said side braces, the side braces of saidbackrest frame further including diagonal walls which extend angularlyinwardly and rearwardly from the respective front walls thereof toportions of the respective inner side walls thereof.
 2. In theautomobile seat of claim 1, the widths of the side braces of saidbackrest frame having upwardly decreasing widths extents, the sidebraces of said backrest frame substantially defining an outer contour ofsaid backrest.
 3. In the automobile seat of claim 1, the side braces ofsaid backrest frame having open rear sides, having the side braces ofsaid backrest frame downwardly increasing structural depths as definedby the distances between the open rear sides thereof and the respectivefront walls thereof, said adjusting means being pivotally attached toeach of the side braces of said backrest frame at a point which isadjacent the lower end of and also adjacent the open rear side of therespective side brace of said backrest frame.